A driveline disconnect clutch may open and close to selectively isolate portions of a driveline. For example, a driveline disconnect clutch may mechanically isolate an engine from a driveline integrated starter/generator and a transmission. The driveline disconnect clutch allows the engine to work with the driveline integrated starter/generator, or alternatively, it allows the engine to operate in isolation from the driveline integrated starter/generator. However, it may be difficult to adjust operation of the driveline disconnect clutch to compensate for clutch degradation without vehicle occupants noticing the driveline disconnect clutch being actuated.
The inventors herein have recognized the above-mentioned disadvantages and have developed a driveline disconnect clutch adaptation method, comprising: adjusting application force of a driveline disconnect clutch in a vehicle driveline in response to a torque sensor while an engine in the vehicle driveline is not combusting air and fuel.
By monitoring a torque sensor while an engine is stopped and while a driveline disconnect clutch is being engaged, it may be possible to update a driveline disconnect transfer function or compensate the driveline disconnect clutch without vehicle occupants taking notice. For example, a driveline integrated starter/generator may rotate a transmission input shaft and the driveline disconnect clutch may be at least partially closed to determine where opposite side driveline disconnect clutch plates touch each other. The stopped engine provides resistance to torque that may be observable across the driveline disconnect clutch. The observed torque can be compared to the driveline disconnect clutch transfer function and the driveline disconnect clutch transfer function may be revised at conditions where the driveline disconnect clutch torque does not match the output of a torque sensor. During such a procedure, the driveline integrated starter generator may rotate at a speed that reduces torque flow through a torque converter so that little torque is transferred to vehicle wheels. In this way, the driveline disconnect clutch transfer function may be adapted without notifying vehicle occupants.
The present description may provide several advantages. Specifically, the approach may improve driveline disconnect clutch operation. Further, the approach may be transparent to vehicle occupants.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.